Air-hydraulic rivet gun

ABSTRACT

A rivet gun of the type for setting blind tubular rivets mounted on a mandrel by tensioning the mandrel to the point of rupture. The rivet gun is characterized by an air actuated hydraulically driven mechanism to grip and retract the mandrel and to eject the mandrel when separated from the rivet. The power unit may be fitted with interchangeable rivet setting heads for either inline &#39;&#39;&#39;&#39;straight-on&#39;&#39;&#39;&#39; riveting or a 90* angle head to permit use of the gun in otherwise inaccessible places.

United States Patent Richardson 1 Aug. 12, 1975 [54] AIR-HYDRAULIC RIVETGUN 3,410,128 1 1/1968 Sauter 72/391 3,760,627 9 973 R' 7 [75] Inventor:Russell F. Richardson, St. Paul, II xchdrdson 2/39] mn PrimaryExaminer-C. W. Lanham [73] Assignee: T extron lnc., Providence, R].Assistant Examiner-Gene P. Crosby 22 Filed: Apr. 15, 1974 [21] Appl.No.: 460,729 [57] ABSTRACT A rivet gun of the type for setting blindtubular rivets mounted on a mandrel by tensioning the mandrel to [52]US. Cl. the Point of rupture- The rivet gun is characterized y [5 6 J anair actuated hydraulically driven mechanism to [58] Field of Search72/391, and retract the mandrel and to eject the mandml when separatedfrom the rivet. The power unit may be fitted [56] References cued withinterchangeable rivet setting heads for either in- UNITED STATES PATENTSline straight-0n riveting or a 90 angle head to per- 3,082,898 3/ 1963Bosch 72/391 mit use of the gun in otherwise inaccessible places.3,254,522 6/1966 Elliott 72/39] 3,367,166 2/1968 Newton 72/391 5 Clams,3 Drawmg Flgul'es 5 7fl [8 5/ {l Z 46 48 7/ $3 32 47 /3 0 3 A n n 11 w I3 3 U U U PATENTEDAUBlZiSYS 3,898,833 A g mm 5 AIR-HYDRAULIC RIVET GUNThis invention relates to a gun for setting blind rivets of the type inwhich the rivet is both inserted into the work and secured therein fromthe same side, without access by the operator to both sides of the work.The rivet is set by deformation of the tubular stem of the rivet on theremote side of the work by virtue of expansion of the stem by pullingthe head of the mandrel on which the rivet is mounted into the stem andthen rupturing the mandrel to free it from the rivet.

Rivets for this purpose and guns for setting such rivets are well known.Both manually operable and power operated guns are available. Heavy dutywork and repetitious work over a long period of time, such as on anassembly line, tend to be fatiguing to the operator. The presentinvention is directed to a power operated rivet setting gun of improveddesign characterized by an air actuated hydraulically driven mechanismfor grasping and retracting rivet mandrels.

The invention is illustrated in the accompanying drawings in which:

FIG. 1 is a side elevation of one form of rivet gun according to thepresent invention;

FIG. 2 is a front elevation thereof;

FIG. 3 is a rear elevation thereof;

FIG. 4 is a vertical longitudinal section on an enlarged scale showingthe operating parts in at-rest position;

FIG. 5 is a similar sectional view showing the parts under air andhydraulic pressure just prior to separation of the mandrel from therivet head;

FIG. 6 is a fragmentary sectional view on an enlarged scale showing thegun in engagement with a rivet mandrel just prior to separation;

FIG. 7 is a side elevation of another form of rivet gun according to thepresent invention having a right angle head; and

FIG. 8 is a fragmentary longitudinal section showing details ofconstruction of that angle head.

Referring now to the drawings, and particularly to FIGS. 1 through 6,the rivet gun comprises a power unit, indicated generally at 10, and oneform of interchangeable rivet setting head for in-line work, indicatedgenerally at 11. The power unit includes a body having a pistol griphandle portion 12 and an integral air cylinder housing 13. Handle 12 isprovided with a recess 14 for receiving a palm grip trigger l5 pivotallyheld on pin 16. Handle 12 is also provided with a longitudinal passageor channel 17 extending from the free end of the handle into triggerrecess 14.

A fitting 18 is inserted into the free end of passage 17 for the purposeof connecting the rivet gun to a source of compressed air or other gasunder pressure. A hollow tubular plunger pin 19 is inserted into passage17 from the trigger recess. A cam 20 on trigger l5 bears against thehead of plunger pin 19 which is spring biased by a light coil spring 21to be normally urged upward into the trigger recess urging the triggerinto its at-rest position. A valve disc 22 lies in passage 17 betweenthe inner ends of plunger pin 19 and air fitting 18, normally urged intosealing engagement with annular valve seat 23 by coil spring 24.

When trigger is squeezed, cam bearing against the end of plunger pin 19compresses spring 21 and causes valve disc 22 to be unseated,compressing spring 24. This permits air to enter through passage 17 intoair passage 25 to chamber 26 within air cylinder housing 13. Whentrigger 15 is released, spring 21 retracts plunger pin 19 and returnsthe trigger to its at-rest position. At the same time, spring 24 reseatsvalve disc 22 on seat 23 to shut off the supply of air to the rivet gun.Air bleeding from chamber 26, as explained in detail hereinafter, isforced out through passage 25 into passage 27 and the open end of pin 19and out through bleeder holes 27 and passage 28 to the atmosphere.

An air ram or piston 29 is disposed in chamber 26 for reciprocalmovement therein. The outer perimeter of piston 29 is provided with anannular groove into which is fit a resilient O-ring 30 for sealingengagement with the inside cylinder wall. The air cylinder chamber isclosed by means of a cap 31 inserted therein. An annular seal ring 32 isseated in the opposite end of chamber 26 from which a bleed hole 33permits escape of air from chamber 26 on the operating stroke of piston29.

An hydraulic cylinder housing 34 is connected to the air cylinderhousing. Housing 34 encloses a pair of spaced apart chambers 35 and 36interconnected by passage 37 and adapted to contain hydraulic fluid.Hydraulic fluid chamber 35 is in axial alignment with air chamber 26.One end 38 of housing 34 extends through a central passage 39 in aircylinder housing 13 and is rigidly fixed therein by means of a lock nut40.

An hydraulic ram 41 is rigidly secured to air piston 29 in axialalignment therewith, as by means of nut 42. Ram 41 extends intohydraulic chamber 35 through a restricted passage having a pair ofannular grooves therein fitted with resilient seal rings to prevent lossof hydraulic fluid. Upon admission of air into chamber 26 behind airpiston 29, the piston and ram 41 are moved forwardly. As ram 41 advancesinto chamber 35, it pushes the noncompressible hydraulic fluid thereinthrough passage 37 into chamber 36 which overlies chamber 35.

Chamber 36 is closed at one end by means of a back cap 46 to which adeflector 47 is attached by means of a threaded ring or collar 48. Anhydraulic piston 49 is disposed in chamber 36 for reciprocal movementtherein. The peripheral edge of piston 49 is provided with a groove inwhich is seated a resilient seal ring 50 held in place by an expansionwasher. Piston 49 is provided with a forwardly extending stem 51 and arearwardly extending stem 52.

The free end of stem 52 fits into a central passage 53 in back cap 46for reciprocal movement therein. Piston 49 is spring biased by means ofa heavy coil spring 54 normally urging the piston to an at-rest forwardposition adjacent passage 37. Stem 51 extends through a passage in theforward wall of housing 34 sealed against leakage of hydraulic fluid, asby means of a pair of resilient O-rings set in annular grooves in thepassage. A central passage 58 extends through piston 49 and its stems 51and 52 for ejection of spent mandrels.

A tubular nose housing 59 having an internally threaded base 60 issecured to the externally threaded boss 61 on the forward wall ofhydraulic housing 34. The free forward end 62 of hydraulic piston stem51 is externally threaded and has an adjusting nut 63 and tubularpulling head 64 secured thereon. The forward end of pulling head 64 isexternally threaded to receive annular jaw case 65 whose inner taperingwalls engage a plurality of mandrel gripping jaws 66. A jaw pusher 67 isdisposed within pulling head 64 and jaw case 65 biased by coil spring 68to maintain force on jaws 66 constantly urging the jaws toward theforward end of the jaw case 65 into engagement with the inner wallsthereof.

As seen in FIG. 4, when the parts are in at-rest position with spring 54holding hydraulic piston 49 in the forward end of chamber36, jaw case 65bears against the inside forward end of the nose housing. The inner orrearward end of nose piece 69 bears against jaws 66 spreadingthem apartand pushing them inwardly into jaw case 65 pushing jaw pusher 67rearwardly and compressing spring 68. Jaw pusher 67 has a centralpassage 70 and nose piece 69 has a central passage 71, both in alignmentwith passage 58 to receive and eject a mandrel.

As seen in FIG. 6, passage 71 in the nose piece serves as a central borein which to receive the mandrel 72 of a conventional blind rivet. Such arivet has a hollow tubular shank or body 74 which extends through thework piece to be riveted (here shown as composed of two plates to beriveted together) and an annular flanged head 75, which may be flat ordomed or counter-sunk, and engages the operatorside of the work. Themandrel 72 is inserted through the rivet in the reverse direction, thatis, toward the operators side with the head 76 of the mandrel at theopposite end from the head 75 of the rivet. As seen in FIG. 4, when thejaws are spread apart when the mechanism is in at-rest position, themandrel is easily inserted.

When the rivet gun is connected to a source of air or other gas underpressure and trigger is depressed to move air piston 29 forward, asdescribed above, ram 41 advancing in hydraulic chamber 35 forces thehydraulic fluid therein through passage 37 into chamber 36. As thehydraulic fluid fills chamber 36, it moves hydraulic piston 49rearwardly compressing spring 54. As piston 49 moves rearwardly, itpulls stem 51 and along with it pulling head 64 and jaw case 65. As thejaw case 65 is drawn backwardly from nose piece 69, force on spring 68is withdrawn causing it to expand, moving jaw pusher 67 forwardly andcausing the jaws to close. This force in combination with the rearwardforce exerted by the inside tapered surfaces of the jaw case 65 againstthe jaws 66 forces the jaws into tight gripping engagement with mandrel72. As the rearwardly directed pulling force continues, the head 76 ofmandrel 72 is forced into and expands the outer end of tubular body 74of the rivet tightening it in place in the work piece and severing themandrel from the head. The mandrel then may pass rearwardly throughpassages 70, 58 and 53. Deflector 47 protects the operator from injuryin the event the mandrel is forcefully ejected.

When pressure on the trigger is released, piston 49 is returned to itsat-rest position by force exerted by spring 54, returning the pullinghead and jaw case to their at-rest positions ready to receive anothermandrel. Hydraulic fluid is forced from chamber 36 through passage 37into hydraulic chamber 35. Ram 41 and air piston 29 are returned totheir at-rest positions. Air from air piston chamber 26 is bled to theatmosphere as already described.

Referring now to FIGS. 7 and 8, there is shown a rivet gun with analternative riveting head 80 for setting rivets in inaccessible placesby exerting force at an angle of 90 relative to the direction of forceexerted by the power unit. As is explained in further detailhereinafter, angle head 80 is interchangeable with the on-line rivethead 11 previously described, using the same power unit and operating ingenerally the same manner with the exceptions noted below.

In US. Pat. No. 3,760,627, issued Sept. 25, 1973, of which the presentapplicant is co-patentee, there is disclosed an angle head rivet gun,the basic structure and operation of which, except for the power source,are generally the same as described herein. The disclosure of thatpatent is incorporated herein by reference.

The angle rivet setting head comprises a hollow tubular body 82internally threaded at one end to receive a nose piece 83 having arestricted bore which is likewise internally threaded to receive abushing 84. Bushing 84 has a central bore in which to receive themandrel of a conventional blind rivet. A pulling head 89 reciprocateswithin the hollow body 82. The forward end of pulling head 89 isexternally threaded and adapted to receive chuck or jaw case 90 whosebore is tapered to receive a pair of tapered jaws 91 which function toengage the shank of a mandrel. Pulling head 89 has a central bore 92extending axially through its length. Bore 92 is of reduced diameter atits rearward end providing a shoulder against which one end of a coilspring 94 bears. A tubular sleeve 95 within bore 92 functions as a jawactuating member, one end of sleeve 95 bearing against jaws 91 and theopposite end bearing against spring 94 to maintain the jaws in constantgripping engagement with the mandrel.

The rearward end of pulling head 89 is of reduced diameter andreciprocates in passage 96 in the rearward end of housing 22 oppositefrom the nose piece. A heavy coil spring 97 surrounds the reduceddiameter end of pulling head 89, one end of spring 97 bearing against ashoulder formed on the pulling head and the other end bearing against aninternal shoulder 98 within the body. As illustrated in the aforesaidpatent, the opposite sides of the pulling head are flattened to providea pair of recesses, each having a rearward shoulder against which a cam99 of a cam arm lever 100 bears.

Angle head 80 includes an elongated tubular housing 101, the upper endof which is fixed in a tubular sleeve 102 disposed at right angles tothe longitudinal axis of housing 82 and having an opening 103 therein.Tubular housing 82 is provided with an opening 104 about midway betweenits ends. A pair of parallel spaced apart gusset plates 105 generallyenclose the space between openings 103 and 104. A pair of parallelspaced apart crank arm levers 100 are pivotally supported between thegusset plates on a pin 106. Cam arm 99 extends through opening 104. Camarm 107 extends through opening 103 embracing the sides of pulling shaft108 and engaging pin 109 extending transversely through the pullingshaft. The opposite end of pulling shaft 108 is threaded and providedwith a coupling nut or threaded sleeve 110 by which the pulling shaft isconnected to the threaded end of stem 51 of hydraulic piston 49.

In order to hold the pulling shaft against rotation within tubular body101 to permit this connection to be made, pin 109 is of sufficientlength that its ends extend into slots 1 1 1 formed in sleeve 102. Forsafety reasons, the ends of pin 109 may be received in a pair ofinternal longitudinal grooves formed in the sleeve, or a protectivecover may be snapped over the slot area. Tubular body 101 is internallythreaded at l 12 to permit attachment of the angle head to the powerunit by screwing onto threaded boss 61. Sleeve 102 is freely rotatableon ference is that the pulling force exerted by piston 49 is transmittedto pulling shaft 108. Pin 109 bearing against cam arm 107 causes crankarm 100 to rotate on its pivot. This translates the pulling forcethrough 90, causing cam arm 99 to exert pulling force on pulling head89. Thereafter the operation is the same as already described inconnection with the in-line head. Although the angle rivet setting headis described and illustrated as being disposed at a right angle relativeto the axis of the pulling force exerted by the power unit, the head maybe disposed at an angle other than 90 with only minor modification ofthe levers 100 and their supporting structure.

It is apparent that many modifications and variations of this inventionas hereinbefore set forth may be made without departing from the spiritand scope thereof. The specific embodiments described are given by wayof example only and the invention is limited only by the terms of theappended claims.

The embodiments of the invention in which an exclusive property orprivelege is claimed are defined as follows:

1. A rivet gun for setting blind rivets, said gun comprising:

A. a setting head for engaging and pulling the mandrel of a blind rivet,

B. a body including force exerting means for applying pulling force tosaid setting head, the direction of said force being generallylongitudinal of said body,

C. said force exerting means comprising 1. a first hydraulic pressurechamber within said body having a piston reciprocable therein generallylongitudinally of the body,

2. stem means movable with said piston in the same direction,

3. means connecting said stem means to the setting head to operate thesame,

4. a second hydraulic pressure chamber disposed within said body inparallel closely spaced apart relation to the first chamber, saidchambers being connected through an intercommunicating passage withinsaid body,

5. a piston reciprocable in said second chamber,

6. a third pneumatic pressure chamber within said body in axialalignment with said second chamber,

7. a piston reciprocable in said third chamber and connected to thepiston in said second chamber for simultaneous movement thereof,

8. means adapted to connect said third chamber to a source of gas underpressure, and

9. means to regulate flow of gas to said third chamber,

D. a pistol grip handle on said body adjacent to said third chamber.

2. A rivet gun according to claim 1 further characterized in that saidsetting head is replaceable and interchangeable with other setting headsand includes a tubular housing detachably secured to said body and areciprocable pulling head within said housing detachably secured to saidpiston stem,

A. said pistion stem extending from said body through a coaxial passagein an externally threaded boss on the exterior of the body,

B. said setting head housing being internally threaded for attachmentthereto,

C. said piston stem being extemally threaded at one end, and I D. saidpulling head being internally threaded for attachment thereto.

3. A rivet gun according to claim 1 further characterized in that saidsetting head is secured to said body with the longitudial axis of saidsetting head disposed at an angle relative to the longitudinal axis ofsaid body and the direction of force applied by said force exertingmeans.

4. A rivet gun according to claim 3 further characterized in that saidsetting head is replaceable and interchangeable with other setting headsand includes:

A. an elongated tubular housing internally threaded at one end, thelongitudinal axis of said tubular housing being in alignment with saidbody and the direction of force applied by said force exerting means andattached to said body through an externally threaded boss on theexterior of said body surrounding a passage coaxial with said pistonstem,

B. a tubular setting head housing secured to the opposite end of saidelongated tubular housing, the longitudinal axis of said setting headbeing disposed at an angle relative to the longitudinal axis of saidelongated tubular housing,

C. a pulling shaft disposed within said elongated longitudinal housingand detachably secured at one end to said piston stem; and

B. pivotal crank arm lever means interconnecting said pulling head andsaid pulling shaft for transmission of force from said pulling shaft toreciprocate said pulling head.

5. A rivet gun for setting blind rivets, said gun comprising:

A. a setting head for engaging and pulling the mandrel of a blind rivet,

B. a body including force exerting means for applying pulling force tosaid setting head, the direction of said force being generallylongitudinal of said body and setting head, said force exerting meanscomprising l. a first hydraulic pressure chamber within said body havinga piston reciprocable therein generally longitudinally of the body,

2. externally threaded stem means movable with said piston in the samedirection and extending from said body through a coaxial passage in anexternally threaded boss on the exterior of the body,

3. a second hydraulic pressure chamber disposed within said body inparallel closely spaced apart relation to the first chamber, saidchambers being connected through an intercommunicating passage withinsaid body,

4. a piston reciprocable in said second chamber,

5 a third pneumatic pressure chamber within said body in axial alignmentwith said second chamber, and

6. a piston reciprocable in said third chamber and connected to thepiston in said second chamber for simultaneous movement thereof,

C. an internally threaded tubular setting head housing detachablysecured to the externally threaded boss on said body,

D. a reciprocable internally threaded pulling head within said housingdetachably secured to said piston stem,

E. a longitudinal axial passage extending through said setting head. thepiston in said first chamber, the stern thereof and said body forpassage of used rivet mandrels therethrough,

sage means.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3 ,898,833 v DATED August 12 1975 |Nv 0R(5) Russell P Richardson It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 2, line 8, "27" should be 17-.

Column 3, line 22, "operator'side" should be -operator's side-- Column5, line 25, "privelege" should be privi1ege.

Signed and Sealed this twenty-eight Day Of October 1975 [SEAL] A ttes t:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner uflarentsand Trademarks

1. A rivet gun for setting blind rivets, said gun comprising: A. asetting head for engaging and pulling the mandrel of a blind rivet, B. abody including force exerting means for applying pulling force to saidsetting head, the direction of said force being generally longitudinalof said body, C. said force exerting means comprising
 1. a firsthydraulic pressure chamber within said body having a piston reciprocabletherein generally longitudinally of the body,
 2. stem means movable withsaid piston in the same direction,
 3. means connecting said stem meansto the setting head to operate the same,
 4. a second hydraulic pressurechamber disposed within said body in parallel closely spaced apartrelation to the first chamber, said chambers being connected through anintercommunicating passage within said body,
 5. a piston reciprocable insaid second chamber,
 6. a third pneumatic pressure chamber within saidbody in axial alignment with said second chamber,
 7. a pistonreciprocable in said third chamber and connected to the piston in saidsecond chamber for simultaneous movement thereof,
 8. means adapted toconnect said third chamber to a source of gas under pressure, and 9.means to regulate flow of gas to said third chamber, D. a pistol griphandle on said body adjacent to said third chamber.
 2. stem meansmovable with said piston in the same direction,
 2. externally threadedstem means movable with said piston in the same direction and extendingfrom said body through a coaxial passage in an externally threaded bosson the exterior of the body,
 2. A rivet gun according to claim 1 furthercharacterized in that said setting head is replaceable andinterchangeable with other setting heads and includes a tubular housingdetachably secured to said body and a reciprocable pulling head withinsaid housing detachably secured to said piston stem, A. said pistionstem extending from said body through a coaxial passage in an externallythreaded boss on the exterior of the body, B. said setting head housingbeing internally threaded for attachment thereto, C. said piston stembeing externally threaded at one end, and D. said pulling head beinginternally threaded for attachment thereto.
 3. A rivet gun according toclaim 1 further characterized in that said setting head is secured tosaid body with the longitudial axis of said setting head disposed at anangle relative to the longitudinal axis of said body and the directionof force applied by said force exerting means.
 3. a second hydraulicpressure chamber disposed within said body in parallel closely spacedapart relation to the first chamber, said chambers being connectedthrough an intercommunicating passage within said body,
 3. meansconnecting said stem means to the setting head to operate the same,
 4. asecond hydraulic pressure chamber disposed within said body in parallelclosely spaced apart relation to the first chamber, said chambers beingconnected through an intercommunicating passage within said body,
 4. apiston reciprocable in said second chamber, 5 a third pneumatic pressurechamber within said body in axial alignment with said second chamber,and
 4. A rivet gun according to claim 3 further characterized in thatsaid setting head is replaceable and interchangeable with other settingheads and includes: A. an elongated tubular housing internally threadedat one end, the longitudinal axis of said tubular housing being inalignment with said body and the direction of force applied by saidforce exerting means and attached to said body through an externallythreaded boss on the exterior of said body surrounding a passage coaxialwith said piston stem, B. a tubular setting head housing secured to theopposite end of said elongated tubular housing, the longitudinal axis ofsaid setting head being disposed at an angle relative to thelongitudinal axis of said elongated tubular housing, C. a pulling shaftdisposed within said elongated longitudinal housing and detachablysecured at one end to said piston stem; and B. pivotal crank arm levermeans interconnecting said pulling head and said pulling shaft fortransmission of force from said pulling shaft to reciprocate saidpulling head.
 5. A rivet gun for setting blind rivets, said guncomprising: A. a setting head for engaging and pulling the mandrel of ablind rivet, B. a body including force exerting means for applyingpulling force to said setting head, the direction of said force beinggenerally longitudinal of said body and setting head, said forceexerting means comprising
 5. a piston reciprocable in said secondchamber,
 6. a third pneumatic pressure chamber within said body in axialalignment with said second chamber,
 6. a piston reciprocable in saidthird chamber and connected to the piston in said second chamber forsimultaneous movement thereof, C. an internally threaded tubular settinghead housing detachably secured to the externally threaded boss on saidbody, D. a reciprocable internally threaded pulling head within saidhousing detachably secured to said piston stem, E. a longitudinal axialpassage extending through said setting head, the piston in said firstchamber, the stem thereof and said body for passage of used rivetmandrels therethrough, F. a pistol grip handle on said body adjacentsaid third chamber, G. passage means in said handle for passage of gasunder pressure to the third chamber and bleeding of gas from saidchamber to the atmosphere, and H. trigger actuated valve means in saidhandle for alternately controlling flow of gas through said passagemeans.
 7. a piston reciprocable in said third chamber and connected tothe piston in said second chamber for simultaneous movement thereof, 8.means adapted to connect said third chamber to a source of gas underpressure, and
 9. means to regulate flow of gas to said third chamber, D.a pistol grip handle on said body adjacent to said third chamber.